UNE GEN CHEM 2 MIDTERM NEWEST ACTUAL 2025/2026 EXAM QUESTIONS AND CORRECT
ANSWERS.VERIFIED/GRADED A+
Question 1
Which of the following best describes an adhesive force?
A) The result of intermolecular forces that attract identical molecules to each other.
B) The result of intermolecular forces that attract different molecules together.
C) The force required to break a covalent bond within a molecule.
D) The pressure exerted by a gas on the walls of its container.
E) The energy required to move an electron to a higher energy level.
Correct Answer: B) the result of intermolecular forces that attract different molecules
together
Rationale: Adhesive forces are the attractive forces between unlike molecules, such as water
molecules sticking to the glass walls of a tube. Cohesive forces, by contrast, are attractions
between like molecules.
Question 2
What is the structural composition of a metallic solid?
A) Positively and negatively charged ions arranged in a rigid lattice.
B) Discrete molecules held together by dipole-dipole forces.
C) Atoms with nuclei in a "sea" of delocalized electrons.
D) Long chains of polymers cross-linked by hydrogen bonds.
E) A single giant molecule with all atoms covalently bonded.
Correct Answer: C) are composed of atoms, with nuclei in a "sea" of delocalized electrons
Rationale: Metallic bonding is characterized by a lattice of metal cations surrounded by a
mobile "sea" of valence electrons that are free to move throughout the structure, accounting
for high conductivity.
Question 3
Acetonitrile (𝑪𝑯𝟑 𝑪𝑵) has a 𝚫𝑯𝒗𝒂𝒑 of 34.2 kJ/mol. How much heat is removed when 2.3 g of
acetonitrile evaporates? (Molar mass of 𝑪𝑯𝟑 𝑪𝑵 ≈ 𝟒𝟏. 𝟎𝟓 g/mol )
A) 78.6 kJ
B) 1.92 kJ
C) 14.8 kJ
D) 0.056 kJ
E) 34.2 kJ
Correct Answer: B) 1.92 kJ
Rationale: First, calculate the moles: 𝟐. 𝟑 g/𝟒𝟏. 𝟎𝟓 g/mol = 𝟎. 𝟎𝟓𝟔𝟎 moles
. Then, multiply by the enthalpy of vaporization: 𝟎. 𝟎𝟓𝟔𝟎 mol × 𝟑𝟒. 𝟐 kJ/mol = 𝟏. 𝟗𝟐 kJ
.
, Page 2
Question 4
In a phase diagram, what does the critical temperature represent?
A) The temperature at which all three phases coexist in equilibrium.
B) The temperature at which a solid converts directly to a gas.
C) The maximum temperature that a liquid can exist, regardless of pressure.
D) The temperature at which the vapor pressure equals 1 atm.
E) The lowest temperature at which a substance can be a solid.
Correct Answer: C) the maximum temperature that a liquid can exist, regardless of pressure
Rationale: Above the critical temperature, the substance becomes a supercritical fluid, where
the distinction between liquid and gas phases disappears, no matter how much pressure is
applied.
Question 5
Under what conditions is a liquid most likely to rise in a capillary tube?
A) When cohesive forces are stronger than adhesive forces.
B) When the density of the liquid is greater than the density of the tube.
C) When the adhesive forces are stronger than the cohesive forces.
D) When the liquid is non-polar and the tube is polar.
E) When the temperature is exactly at the boiling point.
Correct Answer: C) the adhesive forces are stronger than the cohesive forces
Rationale: Capillary action occurs when the attraction between the liquid molecules and the
tube walls (adhesion) is greater than the attraction between the liquid molecules themselves
(cohesion), pulling the liquid up.
Question 6
Which expression calculates the heat required to convert 100 g of liquid water at 12°C to
steam at 135°C?
A) (𝒎 × 𝒄 × 𝚫𝑻)𝒘𝒂𝒕𝒆𝒓 + (𝒎 × 𝒄 × 𝚫𝑻)𝒔𝒕𝒆𝒂𝒎
B) (𝒏 × 𝚫𝑯𝒗𝒂𝒑)
C) (𝒎 × 𝒄 × 𝚫𝑻)𝒘𝒂𝒕𝒆𝒓 + (𝒏 × 𝚫𝑯𝒗𝒂𝒑 ) + (𝒎 × 𝒄 × 𝚫𝑻)𝒔𝒕𝒆𝒂𝒎
D) (𝒎 × 𝒄 × 𝚫𝑻)𝒘𝒂𝒕𝒆𝒓 + (𝒏 × 𝚫𝑯𝒇𝒖𝒔 ) + (𝒎 × 𝒄 × 𝚫𝑻)𝒔𝒕𝒆𝒂𝒎
E) (𝒎 × 𝚫𝑯𝒗𝒂𝒑 ) × 𝚫𝑻
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Correct Answer: C) (m x c x ΔT)water + (n x ΔHvap) + (m x c x ΔT)steam
Rationale: The process involves three steps: heating the liquid to 100°C, the phase change at
100°C (vaporization), and heating the resulting steam to 135°C.
Question 7
How is the enthalpy of vaporization (𝚫𝑯𝒗𝒂𝒑) defined?
A) The energy change when a substance changes from solid to liquid.
B) The energy change when a substance changes from liquid to gas phase.
C) The energy required to break one mole of a specific covalent bond.
D) The energy released when a gas is compressed into a solid.
E) The heat required to raise 1 gram of a substance by 1 degree Celsius.
Correct Answer: B) the energy change when a substance changes from liquid phase to gas
phase
Rationale: 𝚫𝑯𝒗𝒂𝒑 measures the amount of energy required to overcome intermolecular forces
in the liquid phase to enter the gaseous phase.
Question 8
Which of the following molecules will have the strongest dipole-dipole attraction?
A) 𝑪𝑪𝒍𝟒
B) 𝑵𝑪𝒍𝟑
C) 𝑩𝑪𝒍𝟑
D) 𝑪𝒍𝟐
E) 𝑪𝑯𝟒
Correct Answer: B) NCl3
Rationale: 𝑪𝒍𝟐 is non-polar. 𝑪𝑪𝒍𝟒 and 𝑩𝑪𝒍𝟑 are symmetric, so their bond dipoles cancel out,
making them non-polar. 𝑵𝑪𝒍𝟑 is trigonal pyramidal and asymmetric, resulting in a net
molecular dipole.
Question 9
What characterizes a dispersion force?
A) The attraction between a permanent dipole and an ion.
, Page 4
B) The sharing of electrons between two metal atoms.
C) The attraction of temporary dipoles produced by random asymmetries in electron motion.
D) The attraction between a hydrogen atom and a lone pair on Nitrogen, Oxygen, or Fluorine.
E) A force that only exists in ionic solids.
Correct Answer: C) the attraction of temporary dipoles produced by random asymmetries in
electron motion
Rationale: Dispersion forces (London forces) occur in all molecules due to the instantaneous
movement of electrons creating temporary dipoles that induce dipoles in neighboring atoms.
Question 10
What is the molality of 22.3 mg of Vitamin D (𝑪𝟐𝟕 𝑯𝟒𝟒 𝑶, 384.6 g/mol ) in 50.0 mL of hexane
(density = 0.661 g/mL)?
A) 𝟏. 𝟏𝟔 × 𝟏𝟎−𝟑 m
B) 𝟏. 𝟕𝟓 × 𝟏𝟎−𝟑 m
C) 𝟓. 𝟖𝟎 × 𝟏𝟎−𝟓 m
D) 𝟎. 𝟒𝟒𝟔 m
E) 𝟐. 𝟑𝟏 × 𝟏𝟎−𝟐 m
Correct Answer: B) 1.75*10^-3 m
Rationale: Moles Vitamin D = 𝟎. 𝟎𝟐𝟐𝟑 g/𝟑𝟖𝟒. 𝟔 g/mol = 𝟓. 𝟕𝟗𝟖 × 𝟏𝟎−𝟓 mol
. Mass hexane = 𝟓𝟎. 𝟎 mL × 𝟎. 𝟔𝟔𝟏 g/mL = 𝟑𝟑. 𝟎𝟓 g = 𝟎. 𝟎𝟑𝟑𝟎𝟓 kg
. Molality = 𝟓. 𝟕𝟗𝟖 × 𝟏𝟎−𝟓 mol/𝟎. 𝟎𝟑𝟑𝟎𝟓 kg = 𝟏. 𝟕𝟓 × 𝟏𝟎−𝟑 m
.
Question 11
Which of the following aqueous solutions will have the lowest electrical conductivity?
A) 0.1 M potassium chloride, 𝑲𝑪𝒍
B) 0.1 M sodium sulfate, 𝑵𝒂𝟐 𝑺𝑶𝟒
ANSWERS.VERIFIED/GRADED A+
Question 1
Which of the following best describes an adhesive force?
A) The result of intermolecular forces that attract identical molecules to each other.
B) The result of intermolecular forces that attract different molecules together.
C) The force required to break a covalent bond within a molecule.
D) The pressure exerted by a gas on the walls of its container.
E) The energy required to move an electron to a higher energy level.
Correct Answer: B) the result of intermolecular forces that attract different molecules
together
Rationale: Adhesive forces are the attractive forces between unlike molecules, such as water
molecules sticking to the glass walls of a tube. Cohesive forces, by contrast, are attractions
between like molecules.
Question 2
What is the structural composition of a metallic solid?
A) Positively and negatively charged ions arranged in a rigid lattice.
B) Discrete molecules held together by dipole-dipole forces.
C) Atoms with nuclei in a "sea" of delocalized electrons.
D) Long chains of polymers cross-linked by hydrogen bonds.
E) A single giant molecule with all atoms covalently bonded.
Correct Answer: C) are composed of atoms, with nuclei in a "sea" of delocalized electrons
Rationale: Metallic bonding is characterized by a lattice of metal cations surrounded by a
mobile "sea" of valence electrons that are free to move throughout the structure, accounting
for high conductivity.
Question 3
Acetonitrile (𝑪𝑯𝟑 𝑪𝑵) has a 𝚫𝑯𝒗𝒂𝒑 of 34.2 kJ/mol. How much heat is removed when 2.3 g of
acetonitrile evaporates? (Molar mass of 𝑪𝑯𝟑 𝑪𝑵 ≈ 𝟒𝟏. 𝟎𝟓 g/mol )
A) 78.6 kJ
B) 1.92 kJ
C) 14.8 kJ
D) 0.056 kJ
E) 34.2 kJ
Correct Answer: B) 1.92 kJ
Rationale: First, calculate the moles: 𝟐. 𝟑 g/𝟒𝟏. 𝟎𝟓 g/mol = 𝟎. 𝟎𝟓𝟔𝟎 moles
. Then, multiply by the enthalpy of vaporization: 𝟎. 𝟎𝟓𝟔𝟎 mol × 𝟑𝟒. 𝟐 kJ/mol = 𝟏. 𝟗𝟐 kJ
.
, Page 2
Question 4
In a phase diagram, what does the critical temperature represent?
A) The temperature at which all three phases coexist in equilibrium.
B) The temperature at which a solid converts directly to a gas.
C) The maximum temperature that a liquid can exist, regardless of pressure.
D) The temperature at which the vapor pressure equals 1 atm.
E) The lowest temperature at which a substance can be a solid.
Correct Answer: C) the maximum temperature that a liquid can exist, regardless of pressure
Rationale: Above the critical temperature, the substance becomes a supercritical fluid, where
the distinction between liquid and gas phases disappears, no matter how much pressure is
applied.
Question 5
Under what conditions is a liquid most likely to rise in a capillary tube?
A) When cohesive forces are stronger than adhesive forces.
B) When the density of the liquid is greater than the density of the tube.
C) When the adhesive forces are stronger than the cohesive forces.
D) When the liquid is non-polar and the tube is polar.
E) When the temperature is exactly at the boiling point.
Correct Answer: C) the adhesive forces are stronger than the cohesive forces
Rationale: Capillary action occurs when the attraction between the liquid molecules and the
tube walls (adhesion) is greater than the attraction between the liquid molecules themselves
(cohesion), pulling the liquid up.
Question 6
Which expression calculates the heat required to convert 100 g of liquid water at 12°C to
steam at 135°C?
A) (𝒎 × 𝒄 × 𝚫𝑻)𝒘𝒂𝒕𝒆𝒓 + (𝒎 × 𝒄 × 𝚫𝑻)𝒔𝒕𝒆𝒂𝒎
B) (𝒏 × 𝚫𝑯𝒗𝒂𝒑)
C) (𝒎 × 𝒄 × 𝚫𝑻)𝒘𝒂𝒕𝒆𝒓 + (𝒏 × 𝚫𝑯𝒗𝒂𝒑 ) + (𝒎 × 𝒄 × 𝚫𝑻)𝒔𝒕𝒆𝒂𝒎
D) (𝒎 × 𝒄 × 𝚫𝑻)𝒘𝒂𝒕𝒆𝒓 + (𝒏 × 𝚫𝑯𝒇𝒖𝒔 ) + (𝒎 × 𝒄 × 𝚫𝑻)𝒔𝒕𝒆𝒂𝒎
E) (𝒎 × 𝚫𝑯𝒗𝒂𝒑 ) × 𝚫𝑻
, Page 3
Correct Answer: C) (m x c x ΔT)water + (n x ΔHvap) + (m x c x ΔT)steam
Rationale: The process involves three steps: heating the liquid to 100°C, the phase change at
100°C (vaporization), and heating the resulting steam to 135°C.
Question 7
How is the enthalpy of vaporization (𝚫𝑯𝒗𝒂𝒑) defined?
A) The energy change when a substance changes from solid to liquid.
B) The energy change when a substance changes from liquid to gas phase.
C) The energy required to break one mole of a specific covalent bond.
D) The energy released when a gas is compressed into a solid.
E) The heat required to raise 1 gram of a substance by 1 degree Celsius.
Correct Answer: B) the energy change when a substance changes from liquid phase to gas
phase
Rationale: 𝚫𝑯𝒗𝒂𝒑 measures the amount of energy required to overcome intermolecular forces
in the liquid phase to enter the gaseous phase.
Question 8
Which of the following molecules will have the strongest dipole-dipole attraction?
A) 𝑪𝑪𝒍𝟒
B) 𝑵𝑪𝒍𝟑
C) 𝑩𝑪𝒍𝟑
D) 𝑪𝒍𝟐
E) 𝑪𝑯𝟒
Correct Answer: B) NCl3
Rationale: 𝑪𝒍𝟐 is non-polar. 𝑪𝑪𝒍𝟒 and 𝑩𝑪𝒍𝟑 are symmetric, so their bond dipoles cancel out,
making them non-polar. 𝑵𝑪𝒍𝟑 is trigonal pyramidal and asymmetric, resulting in a net
molecular dipole.
Question 9
What characterizes a dispersion force?
A) The attraction between a permanent dipole and an ion.
, Page 4
B) The sharing of electrons between two metal atoms.
C) The attraction of temporary dipoles produced by random asymmetries in electron motion.
D) The attraction between a hydrogen atom and a lone pair on Nitrogen, Oxygen, or Fluorine.
E) A force that only exists in ionic solids.
Correct Answer: C) the attraction of temporary dipoles produced by random asymmetries in
electron motion
Rationale: Dispersion forces (London forces) occur in all molecules due to the instantaneous
movement of electrons creating temporary dipoles that induce dipoles in neighboring atoms.
Question 10
What is the molality of 22.3 mg of Vitamin D (𝑪𝟐𝟕 𝑯𝟒𝟒 𝑶, 384.6 g/mol ) in 50.0 mL of hexane
(density = 0.661 g/mL)?
A) 𝟏. 𝟏𝟔 × 𝟏𝟎−𝟑 m
B) 𝟏. 𝟕𝟓 × 𝟏𝟎−𝟑 m
C) 𝟓. 𝟖𝟎 × 𝟏𝟎−𝟓 m
D) 𝟎. 𝟒𝟒𝟔 m
E) 𝟐. 𝟑𝟏 × 𝟏𝟎−𝟐 m
Correct Answer: B) 1.75*10^-3 m
Rationale: Moles Vitamin D = 𝟎. 𝟎𝟐𝟐𝟑 g/𝟑𝟖𝟒. 𝟔 g/mol = 𝟓. 𝟕𝟗𝟖 × 𝟏𝟎−𝟓 mol
. Mass hexane = 𝟓𝟎. 𝟎 mL × 𝟎. 𝟔𝟔𝟏 g/mL = 𝟑𝟑. 𝟎𝟓 g = 𝟎. 𝟎𝟑𝟑𝟎𝟓 kg
. Molality = 𝟓. 𝟕𝟗𝟖 × 𝟏𝟎−𝟓 mol/𝟎. 𝟎𝟑𝟑𝟎𝟓 kg = 𝟏. 𝟕𝟓 × 𝟏𝟎−𝟑 m
.
Question 11
Which of the following aqueous solutions will have the lowest electrical conductivity?
A) 0.1 M potassium chloride, 𝑲𝑪𝒍
B) 0.1 M sodium sulfate, 𝑵𝒂𝟐 𝑺𝑶𝟒
